Machines for jetting droplets of viscous medium, e.g. solder paste or glue, onto a substrate are software controlled. The software needs instructions for how to apply the viscous medium to a specific substrate. These instructions are called a jetting program. Thus, the jetting program supports the process of jetting droplets onto the substrate in order to secure that proper amounts of medium are accurately deposited on predetermined spots of the substrate where pads are provided. A pad is a delimited area of a conducting solid material. For example, such a substrate is provided as a printed circuit board, PCB. Leads of the components that are to be mounted on the substrate will be positioned onto the pads, and adhered thereto by means of the medium, which is electrically conducting.
Typically, the preprocessing that generates the jetting program is performed off-line, and involves some manual steps performed by an operator.
Thus, generally, the generation of the jetting program involves importing, to a generation program, substrate data relating to a unique substrate, or a unique set of identical substrates; and defining, on basis of the substrate data, where on the substrate the droplets are to be jetted.
In a prior art example of a method for generating a jetting program, a program called CADImport is used in the off-line preprocessing phase, generating a jetting program, and a program called Fluidmove®, vended by Asymtek, receives and executes the jetting program upon command. Thus, CADImport is used for importing and processing CAD data or the like about a PCB, and Fluidmove® is used for running the jetting machine on basis of the processed CAD data. The CAD data comprises pad data, i.e. data about position on the PCB and extension of each individual pad, as well as data about position, name and leads of each individual component that is to be mounted on the PCB. Thus, it is also known which pads each respective component will be using. The positions are defined by x and y coordinates, where an xy coordinate system covers the PCB.
An operator who runs the CADImport program basically programs where the droplets of viscous medium are to be jetted onto the PCB, and more particularly on the pads, such that for each lead of every component there will be provided enough medium, which will be correctly positioned. This is a process which requires knowledge of the size of a single droplet, how many droplets that will be sufficient for covering the needs of a specific lead, and where on the pad each droplet should be placed. Typically, the operator can find data about the droplet size in/by means of CADImport, since machine data are usually provided in advance. However, the appropriate xy coordinates for each droplet must be figured out by the operator based on experience. Once the droplets associated with a component of a particular identification (ID) are programmed, the thus obtained droplet configuration may be stored in a component database. In the future, when a component bearing the same ID appears, the droplet configuration may simply be retrieved from the database.
When all droplet configurations for all components have been programmed, the operator initiates a jetting path generation, that generates a jetting path template for how the jetting machine is going to move the jetting nozzle in order to jet the viscous medium droplets onto the PCB in accordance with the operator's intention. The final jetting data, i.e. the jetting path template, is transferred to the Fluidmove® program, which is used for running the jetting machine accordingly.
In spite of the possibility to store and reuse droplet configuration data for the components it is time consuming for the operator to define where each individual droplet is to be placed for every new component that is not registered in the database. This is because the number of different components is vast, and more or less every day new components are put on the market. Consequently, the database is of limited value.